Wang Xuechun, Ma Zhiye, Xu Shuai, Zheng Dan, Bai Bo, Zong Shichao
Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of the Ministry of Education, Chang'an University, Xi'an 710054, PR China; School of Water and Environment, Chang'an University, Xi'an, 710054, PR China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources, Chang'an University, Xi'an, 710054, PR China.
School of Chemical and Blasting Engineering, Anhui University of Science and Technology, Huainan, 232001, PR China.
Water Res. 2025 Jan 1;268(Pt B):122709. doi: 10.1016/j.watres.2024.122709. Epub 2024 Oct 28.
Solar-driven desalination has emerged as a promising approach to address water scarcity caused by the decreasing supply of freshwater. Reducing the enthalpy of water vaporization is crucial for enhancing the efficiency of solar-powered desalination. In this study, inspired by the Hofmeister effect, we developed a highly hydratable network hydrogel evaporator to achieve a superior evaporation rate in brine compared with pure water. The evaporator comprised a carbonized layer as the photothermal layer and a chitosan aerogel hydrogel as the hydratable matrix. The hydrogel exhibited a dramatically reduced vaporization enthalpy of 1397 J/g and a significant evaporation rate of 2.38 kg m h when exposed to seawater. These results demonstrated the superior performance of hydrogel compared with pure water (1.91 kg m h). Excellent evaporation rates and outstanding salt resistance ensured efficient coordination for practical long-term desalination applications. Further investigations revealed that the remarkable evaporation performance of the carbonized chitosan (CCS) hydrogel in brine environments was attributed to its hydrability, which was regulated by Cl. According to the Hofmeister effect, Cl accelerated the hydration chemistry in CCS and suppressed the associated crystallinity, which resulted in a lower enthalpy of vaporisation owing to a higher amount of intermediate water. With its superior evaporation performance in brine and comprehensive theoretical simulation analysis, this study presents an achievable and economical strategy for simultaneously addressing the water and energy crises.
太阳能驱动的海水淡化已成为解决因淡水供应减少而导致的水资源短缺问题的一种很有前景的方法。降低水汽化焓对于提高太阳能海水淡化效率至关重要。在本研究中，受霍夫迈斯特效应的启发，我们开发了一种具有高水合能力的网络水凝胶蒸发器，以在盐水中实现比纯水更高的蒸发速率。该蒸发器包括作为光热层的碳化层和作为水合基质的壳聚糖气凝胶水凝胶。当暴露于海水中时，该水凝胶的汽化焓显著降低至1397 J/g，蒸发速率高达2.38 kg m⁻² h⁻¹。这些结果表明，与纯水（1.91 kg m⁻² h⁻¹）相比，水凝胶具有更优异的性能。出色的蒸发速率和卓越的耐盐性确保了在实际长期海水淡化应用中的高效协同。进一步研究表明，碳化壳聚糖（CCS）水凝胶在盐水环境中的显著蒸发性能归因于其水合能力，而水合能力由Cl⁻调节。根据霍夫迈斯特效应，Cl⁻加速了CCS中的水合化学过程并抑制了相关的结晶度，由于中间水含量较高，导致汽化焓降低。凭借其在盐水中的优异蒸发性能和全面的理论模拟分析，本研究提出了一种同时解决水危机和能源危机的可行且经济的策略。
